Family level characters:Sponges in this family lack the chelae microscleres that are characteristic of the other families in the Order Poecilosclerida. Instead they have a diverse range of microscleres that may include c- or s-shaped sigmas, comma-like commata and fine, hair-like raphides. This family contains six genera that exhibit examples of the full variety of growth forms from encrusting to cup-shaped, branching and massive.

Order level characters:This order contains the highest diversity of sponge species in the phylum, spread amongst 25 families. Member species have been recorded from all marine habitats. Poecilosclerid sponges are characterised by the presence of both organic (fibre) and inorganic (spicular) skeletal components, both usually well developed. Different spicule and skeletal elements are often localised to particular regions of the sponge. A diverse range of spicule types is displayed throughout this order including the c-shaped chelae microscleres that are peculiar to this order. Examples from 11 of the 25 families are included here.

Taxonomy

Phylum:

Porifera

Class:

Demospongiae

Order:

Poecilosclerida

Family:

Desmacellidae

Genus:

Biemna

General Description

A pale yellow sponge species with encrusting lobate form. Size of about 20 cm.

Biology

This species is a member of a family group that has species known to cause severe dermatitis reactions of the skin on contact. There are over 50 species in this genus occurring in oceans worldwide and over a large depth range.